Khan now confronts the daunting challenge of governing a fractious nuclear power of 220 million people with 39 percent poverty, chronic violence along its border with Afghanistan and a hulking national deficit.

And he must do so under severe budget constraints and new constitutional restrictions on the power of the prime minister’s office. In my analysis as a scholar of Pakistani democracy, Khan will take office as one of the weakest prime ministers in decades.

A return to federalism

Khan ran as a populist and promised to change life for Pakistanis, in particular his main constituency, Pakistan’s struggling urban middle class.

Beyond ongoing financial constraints, Khan will likely struggle to advance his ambitious agenda due to a new system of power distribution in Pakistan that prioritizes local governments.

Like the United States or Canada, Pakistan has a federal government system. Its 1973 Constitution gave Pakistan’s four provinces significant autonomy to run their own affairs, while the federal government manages national issues like foreign affairs, defense and international commerce.

But a series of military coups, dictatorships and martial law have centralized power at the federal level. For decades, Pakistan’s national leaders have exerted almost unchecked power over education, health care, agriculture and other important policy areas.

Seeking to enhance democracy in Pakistan by giving citizens more local control over the policies that affect their daily lives, Pakistan’s Parliament in 2010 amended the Constitution to devolve greater power to Pakistan’s four provinces. The 18th amendment gave provincial governments control over climate change policy, social welfare, education, health care, agriculture and youth education and development.

Now, Khan must fund his ambitious promises – better health care, education and jobs – with half as much money as his predecessors. Perhaps more importantly, he lacks the political jurisdiction to control policy in these issue areas.

As a result, the prime minister-elect will have to rely on Pakistan’s four provincial governments to help him implement his ambitious electoral agenda.

Balochistan’s leadership has no loyalty to Khan. Since the Pakistani armed forces back both Khan and the Balochistan Awami Party, however, their defense agendas may well line up. Balochistan shares a border with Afghanistan and Iran.

Khan has no common ground with the left-wing Pakistan People’s Party, which runs the second most populous province, Sindh. Founded by a prominent Pakistani politician, the late Zulfiqar Ali Bhutto, in 1967, the party currently faces multiple corruption investigations.

Supporters say the charges were engineered by Pakistani military intelligence to hurt the Pakistan People’s Party’s chances in July’s general election. Party leadership has so far refused to work with the prime minister-elect to help him form a governing coalition.

The biggest challenge Khan faces in running Pakistan will likely be the province of Punjab. Its capital, Lahore, is an economic and cultural heavyweight in Pakistan, and Punjab is home to 55 percent of the country’s population.

Khan’s party did moderately well in Punjab this election, but did not win enough votes to form a provincial government. As a result, Khan’s Pakistan Justice Movement is now working to create a governing coalition there.

The alliance his party is cobbling together consists of some two dozen political independents and defectors from other parties, many of whom have frequently changed political parties.

It remains to be seen whether these former competitors and frequent party-hoppers can work well enough together to run Pakistan’s most populous, powerful and prosperous province. Their loyalty to Khan and his agenda is also untested.

Pakistan’s fragile democracy

Despite these obstacles to governance, Khan campaigned as someone who believed he would have full executive power to change Pakistan’s future.

It is possible that the prime minister-elect does not yet understand how the 18th amendment has curtailed his role.

Once he does, federalism in Pakistan may be endangered.

One of the country’s most influential political analysts, Najam Sethi, believes that Khan will seek to repeal of the 18th amendment when he realizes that he now shares a budget with four provincial governments.

That would be a step back for Pakistan as it seeks to create a government by and for the people after seven decades of fitful democracy.